This invention relates generally to antifriction bearings and more particularly to linear motion bearings wherein bearing support is provided to a straight-line or slidably moveable member requiring such support.
There are known in the prior art numerous constructions of linear motion bearings. Such bearings could for example, be of the type disclosed in U.S. PAT. No. 3,767,276 wherein an assembly of inner and outer sleeves retain balls between such sleeves in raceways formed in the sleeve structures to provide bearing support for a shaft slidably received in the assembly. This type of bearing can be relatively expensive to manufacture and its assembly presents special requirements particularly in regard to ball bearing insertion in the sleeve raceways.
Linear bearings are being used in more and more applications wherein relatively slidable members require bearing support, and since competitiveness in the bearing industry is keen, the art has continually sought constructions of linear bearings which are more easily and cheaply manufactured. Thus bearings which utilize segmental parts such as stamped metallic or molded thermoplastic parts have been developed, U.S. PAT. Nos. 3,751,121, 3,951,473, 4,025,128, 4,456,312 and 4,572,591 being illustrative of these types of composite bearing assemblies. These constructions still present difficulties to the manufacturer, particularly in connection with the procedures attending assembly and especially with respect to holding the component parts in bearing array, such as inserting the balls in the raceways and inserting bearing plates in cooperation therewith until means such as a locking ring is fixed in place to hold the various components in final assembled condition. These difficulties are also present in regard to manufacture of bearing assemblies of a type in which a single cylindrical molded thermoplastic cage having plural races is employed in conjunction with an outer sleeve member. Special molding requirements are involved in making the cage member, principally as they relate to the complexity and cost of the dies required for molding the cage.
Although advantages can be gained from the use of certain recent linear bearing construction innovations, e.g., molded thermoplastic raceway segment parts, none of the proposals offered by the prior art provide a fully self-contained unit providing a single line of bearing support which is readily made of simply structured thermoplastic molded parts and easily assembled with ball bearings and bearing plate means so that the unit is capable of use, per se, or in combination with additional like units in a linear bearing configuration for providing bearing support.
The present invention provides a linear motion bearing which can be manufactured as a self-contained bearing unit containing all of the components required for providing a line of bearing support for a relatively slidable member or which can be used with one or more like units to establish a desired or required bearing configuration for such relatively slidable member. The unit is manufactured readily and inexpensively employing thermoplastic molding techniques. The assembling of the several components of the unit is effected very simply without the necessity of complicated tooling and/or fixtures and the units can be supplied as a chain of such wherein each unit is joined to another by integral tab connectors thereby facilitating and simplifying the handling of the units both in assembly operations and installation in bearing support environment.